U.S. Pat. Nos. 6,762,562; 6,853,151; 7,067,992; and U.S. patent application Ser. No. 11/198,633 set forth LED arrays positioned in tubes that are powered by reduced voltage from a ballast. This reduced voltage can be provided with various controls positioned inside or outside of the tubes, so that the illumination from the LED arrays can be varied, or switched to an on or off mode in accordance with illumination requirements that are independent of the main AC voltage lines in the area of the LED lamp as long as the main AC voltage lines are constantly on.
The present invention uses alternate power sources in lieu of the existing ballast as the main source of power to the LED lamp. The present invention discloses new retrofit LED lamps that are powered directly from line voltage alternating current (e.g., 120 Volts RMS at 60 Hz, 220 Volts RMS at 50 Hz), or other input power means where the ballast is removed or bypassed. The line voltage AC can be rectified to DC voltage that is then provided with various controls positioned internal or external to the tubes, so that the illumination from the LED arrays can be varied, or switched to an on or off mode in accordance with the illumination requirements.
Although the present LED lamp invention uses various power control devices to maximize energy savings for replacing fluorescent lamps, the same power control devices, systems, and techniques as disclosed in this specification can also be used for other lamp types including, but not limited to incandescent, halogen, HID, MH, MSR, HPS, phosphorescent, lasers, electro-luminescent, and other types of luminescent lamps for added energy efficiency and savings. In particular, the use of the power control devices can be use in tubular devices that are powered by external power sources including line voltage AC and DC drivers and supplies for the direct replacement of existing fluorescent lamps and devices.
The present invention is shown in FIGS. 87, 88A, 88B, 89A, 89B, 89C, 89D, 90, 91, 92, 93, 94, 95, 96, and 97, and is described in detail later. Before proceeding to such detailed description of FIGS. 87-97, some preliminary comments are now made in relation to the present invention as follows.
A ballast by definition is a device used to provide a starting voltage, and to stabilize and regulate the current in a circuit including fluorescent and discharge lamps. A power supply by definition is a separate unit or a device that supplies power or electrical energy to another device or a group of devices in a system. Since the starting voltage from a ballast is reduced to a lower voltage with the use of a voltage-reducing device, the ballast essentially operates like a current limiting power supply. The LED lamp of the present invention is then designed to work with all types of power supplies and ballasts interchangeably or with direct line voltage alternating current or VAC and even VDC power.
In the present invention, direct line voltage alternating current (VAC) provides the main electrical power to the LED retrofit lamp. For direct line VAC connection, the ballast is removed or bypassed, and the line voltage electrical power may go straight into a rectifying circuit that converts the VAC to VDC to power the various electrical components in the LED lamp. Direct connection to AC power without using a rectifying circuit is now possible. This is the case, for example, when the LEDs used are of the Acriche variety that are specially designed and manufactured by Seoul Semiconductor for direct AC connection. These LEDs can operate off 100, 110, 220, or 230 VAC. An alternate arrangement would be to connect a series of LEDs together to receive the line voltage AC, break down the input voltage evenly across each LED, and then use current limiting means to power the LEDs directly. Ultimately, DC voltage is supplied to other electrical components, including, but not limited to, a computer with its related hardware and software, logic gates, switches, sensors, dimmers, timers, and LED arrays, and other such associated electrical units known in the art.
There can be high transient voltage spikes in any AC or DC system. The sources of the transient voltage spikes can be from lightning, nuclear electromagnetic pulse, high energy switching, high voltage sparks, or electrostatic discharge. They may be found wherever the energy stored in inductors, capacitors, or electromechanical devices such as motors and generators are returned to a circuit. Because these LED lamps are designed for external AC and DC input voltages, there could be the need for voltage surge suppressors, movistors, varistors, inductors, and the like to reduce unwanted electrical voltage spikes and to protect the LED lamps. But these voltage suppression devices are optional. The LED lamp will still operate without these voltage suppression devices. However, without them, the LED lamps become unreliable and not protected from external voltage spikes that may permanently damage the internal electronic components within the LED lamp.
Dimmers as described herein can be conventional SCR or triac type dimmers, duty cycle modulated dimmers, amplitude modulated dimmers, frequency modulated dimmers, direct current voltage dimmers, current drivers, voltage drivers, autotransformers, rheostats, power op-amps, linear amplifiers, transistors, switches, and other types of dimmers can be use in the LED lamp.
Likewise, straight VDC power sources can be connected directly to the LED lamp of the present invention. Some DC power sources that can be used include, but are not limited to batteries, automotive and marine DC systems, AC to DC converters, DC to DC converters, linear and switched DC power supplies, current regulating LED drivers, buck converters, boost converters, buck-boost converters, and other such electrical systems known in the art.
Presently, in the area of fluorescent lighting, the latest energy savings involve the retrofit of existing fluorescent fixtures with new longer-life super T8 or T5 fluorescent lamps in use with new electronic ballasts. In many cases, fully functional electronics and mercury harmful lamps are likewise discarded. In addition, the cost involved for the labor to retrofit and re-wire all the existing fluorescent lighting in a commercial or industrial building can be quite expensive.
A different approach to energy efficient lighting is herewith proposed by disclosing new tubular LED fluorescent retrofit lamps for use with existing or new fluorescent housings where the ballasts are removed or bypassed. The use of energy efficient and environmentally friendly tubular LED retrofit lamps will help eliminate harmful and hazardous mercury waste as produced by present fluorescent lamps. The tubular LED retrofit lamps of the present invention are designed to fit into existing fluorescent sockets to provide direct compatibility and ease of installation. Some benefits of using LEDs as a lighting alternative compared to fluorescent lamps include no mercury, longer life, better energy efficiency, better CRI, no flickering, full dimming capability, and operation in extreme cold conditions.
When Nichia Corporation first introduced the first white LED back in 1996; there were some problems with the new technology. Some of these obstacles included wide manufacturing tolerances for color temperature and intensity, low light output per unit, low efficacy (under 15 to 24 lumens per watt (LPW)), poor lumen maintenance, and lastly, high expense. These drawbacks prevented wide acceptance, promotion, sale, and implementation of LED lamps in the beginning.
Today, high brightness white LEDs are becoming much more popular as large companies like GE, Philips, and Sylvania/Osram have invested billions of dollars towards research and development to improve the performance of the new high brightness and power white LEDs to overcome the initial barriers and bring more usable white LED products to market. For example, Lumileds Lighting, a partnership between Philips Lighting and Hewlett Packard, introduced a new line of Luxeon white LEDs at Lightfair 2005. The solution to the wide manufacturing tolerances for achieving a consistent color temperature and intensity was to introduce color-matched white Luxeon Lamps, each containing multiple white Luxeon LEDs that are selected by advanced binning algorithms. By correctly combining an appropriate mix of LEDs, the Luxeon Lamps themselves have well-controlled and consistent color temperatures of 3200K (warm white), 4100K (commercial white) or 5500K (cool white). Lumileds Lighting intends to release their new Luxeon Rebel high-brightness LEDs in 2007.
The low light output per unit barrier can be overcome by using more LEDs in an array or using more LED dies in a package like the Luxeon K2 and BL Series of LED light engines available from Lumileds and Lamina Ceramics, respectively. Enfis Limited in the United Kingdom also offers a very dense LED die array available in Red, Green, Blue, and Amber colors besides White. Special optics and light gathering reflectors and other optical techniques can be used with the new high brightness and high power LEDs to provide comparable light outputs to conventional light sources.
The new Luxeon white LEDs mentioned before when used in linear lamps, have twice the efficacy of conventional halogen and incandescent lamps. When incorporated into a system, they can exceed the efficacy of fluorescent lighting. For example, a 3200K linear lamp has an efficacy of 32 LPW; a 4100K linear lamp has an efficacy of 40 LPW; a 5500K linear lamp has an efficacy of 50 LPW; and a new and improved 5500K lamp will offer an efficacy of 72 LPW.
Lumen maintenance for white LEDs has also improved with a minimum expected lifetime of 50,000 hours at 70% lumen maintenance. The life would increase with lower drive current and better heat management systems. Lumileds Lighting also publishes a one-year payback period when using the Luxeon white LED linear lamps when compared with a T5 or T8 fluorescent lamp with equal lumen output.
Prices for white LEDs have dropped significantly since their first introduction and particularly with the original discrete 5 mm white LEDs. For example, at introduction, a 5 mm white LED cost about $3-$5 each. Today, they cost about 80 cents in small quantities, and around 35 cents each in larger quantities of up to one million pieces. The cost of the new high power LED die array packages are now the premium, but they too will drop down in price as technology increases, and more LED manufacturers are producing similar white LEDs and lighting fixture manufacturers are using them in new LED products available to the public. Present day white LEDs when used in an array are a viable substitute for fluorescent lamps.
The following paragraphs will compare the differences between a typical new long-life 32-watt T8 fluorescent lamp versus the new tubular LED replacement lamp.
The cost for a typical long-life 32-watt T8 fluorescent lamp is around $5.00 with a life of 20,000 hours including installation. Since LED replacement lamps for fluorescents are unknown in the present market, we can use a comparable linear LED lamp as a base model. Ledtronics, Inc. located in California, presently sells a warm white LED lamp Part Number LED25T10-21W-120AM at a retail price of $79.99. Based on their published data, in an approximate 4-inch space, there are (64) 5 mm white LEDs mounted to a flat FR4 type circuit board. The lamp puts out 134 lumens or 136 foot-candles with a 40-degree beam spread, and consumes 1.86-watts. Obviously, the final cost for a similar tubular LED linear lamp will vary depending on the type and quantity of LEDs used.
Many LED manufacturers are now offering white LEDs with high luminosity flux outputs at relatively lower prices. Based on pricing obtained most recently during the write-up of this application from LED manufacturers like Lumileds, Nichia, and Cree Lighting, the Cree XLamp 7090 white LED is presently the industry's brightest 350 mA packaged LED. A single Cree XLarnp 7090 white LED has a typical luminous or radiant flux of 52 lumens at 350 mA with a color temperature of between 4500K and 8000K. The new Cree XLamp 7090 white LED each consumes a power of 1.4-watts and has a 100 degrees viewing angle. In quantities of one million pieces, the price of each Cree XLamp 7090 white LED is $1.95 USD.
When the Cree XLamp 7090 white LED is used in place of standard 5 mm high brightness white Nichia LEDs, for example, the following calculations result.
Using the standard 32-watt rating of a typical T8 fluorescent lamp as a starting point and dividing by 1.4-watts gives approximately 22.857 Cree XLamp 7090 white LEDs being used in one 4-foot LED lamp of the present invention. Rounding off to a factor of four arrives at a total of 20 Cree XLamp 7090 white LEDs to be used in the new LED replacement lamps. This arrives at an LED acquisition cost of $39.00 or (20×$1.95). With the circuit board, electronics, mechanical parts, and including markup and mass production in very high volume quantities, one can possibly see the basic tubular 4-foot LED retrofit lamp selling for at least $50.00 versus the $5.00 for the T8 fluorescent lamp. The use of the new tubular LED lamp system may cost more initially, but the savings realized over a number of years will justify the initial expense along with the other benefits to follow.
The expected life of the tubular 4-foot LED linear lamp is at least 50,000 hours as compared to the life of a T8 fluorescent lamp of 20,000 hours. Therefore, the tubular LED linear lamp can last 2.5 times longer than the T8 retrofit fluorescent lamp.
A T8 has an overall 360-degree output rating of about 2,700 lumens with a color rendering index or CRI of 82. The tubular 4-foot LED lamp model should produce 1040 (20×52) lumens in a vertical direction beam output distribution over 100-degrees. When compared to the same portion of beam output distribution of 750 lumens (2,700/3.6) over a comparable beam spread of 100-degrees from the T8 fluorescent lamp model, the tubular 4-foot LED lamp produces more light output with a CRI of 90.
Based on the labor required to maintain, repair, and replace a large number of lamps, the average cost including labor and material for retrofitting an existing fluorescent fixture with a T8 20,000-hour fluorescent lamp and a non-dimming electronic ballast is about $25.00, at $5.00 for the lamp, $15.00 for the non-dimming ballast, and $5 for the initial installation. The average cost including labor and material for the same T8 lamp and a dimming electronic ballast is about $50.00, at $5.00 for the lamp, $40 for the dimming ballast, and $5 for the installation. Based on these numbers and the values determined by earlier calculations, we can have the following possible fluorescent fixture retrofit options:
Ballast TypeLampCostRelamping CostTotalMagneticT12$0.00$0.00$0.00MagneticT8$10.00$10.00$20.00Electronic − DimT8$25.00$10.00$35.00Electronic + DimT8$50.00$10.00$60.00Line Voltage VACT8/T12N/AN/AN/AMagneticLED$55.00$0.00$55.00Electronic − DimLED$70.00$0.00$70.00Electronic + DimLED$95.00$0.00$95.00External VAC SourceLED$55.00$0.00$55.00External VDC sourceLED$95.00$0.00$95.00
In the first row, we have an existing fluorescent fixture using an old magnetic ballast and an old T12 type lamp. This serves as the base model with no upgrade done here. In the second row, the old T12 lamp is replaced with a T8 lamp, but the magnetic ballast is left in place. The initial cost of the lamp including labor to install it would be $10.00. The T8 lamp will need to be replaced twice, once at 20,000 hours and a second time at 40,000 hours. With the assumption that the cost of the new lamp including labor to install it is still $5.00, this will add $10.00 giving a final overall cost of $20.00. In the third row, an existing fluorescent fixture is replaced with a new T8 lamp and a new non-dimming electronic ballast. The initial cost of the lamp and ballast including labor is $25.00 added to $10.00 for two lamp changes comes to a final overall cost of $35.00 for this arrangement. In the fourth row the fixture is replaced with an electronic dimming ballast and a new T8 lamp giving a final overall cost of $60.00 for this configuration. A line voltage version of a fluorescent lamp is not applicable.
In the seventh row, the old T12 is retrofitted with a new tubular LED linear lamp, and the old magnetic ballast is kept giving a total cost of $55.00, which includes the cost of the LED lamp estimated at $50.00 and an initial installation labor cost of $5.00. In the eighth row, a new tubular LED linear lamp with a new non-dimming electronic ballast is retrofitted at a total cost of $70.00. In the ninth row, a the fixture is retrofitted with a new tubular LED linear lamp and a new dimming electronic ballast for a total cost of $95.00. In the tenth row, the ballast is removed or bypassed, and a new retrofit tubular LED linear lamp is wired directly to line voltage alternating current or an external VAC source for a total cost of $55.00. In the last row is shown an entry for the use of an external direct-current voltage source for use with a new tubular LED linear lamp. A standard rule for a DC power supply is usually $1 per watt. A 40-watt DC power source priced at $40 along with the basic LED replacement lamp cost of $50 plus $5 for labor creates a total cost of $95.00.
As seen in the table above, two retrofit options give the same final cost. They include replacing the old lamp with a new LED retrofit lamp only, or using the new tubular LED linear retrofit lamp in the existing fixture and removing or bypassing the old ballast, and using direct line voltage AC to power the new LED retrofit lamp. The use of the new LED linear retrofit lamps show a cost savings over replacing the old ballast and T12 lamp with a new dimming electronic ballast and long life T8 lamp if the price of the new basic LED retrofit lamp is priced at $50.00 each, up to a cost of not more than $60.00 each to be competitive.
The new basic LED retrofit lamp is inherently dimmable using standard SCR or triac type wall dimmers and autotransformers or other automatic external energy saving devices. This being the case, the new basic LED retrofit lamps are more comparable to a replacement situation of a T8 lamp with a new dimming ballast than with a T8 lamp and a non-dimming ballast. Obviously, the final decision will be up to the end user's preference and budget cost concerns. The new LED retrofit lamp offers even more advantages over the use of a fluorescent lamp when we look at the energy savings involved when the two lamps are compared in the following paragraph.
Consumption and cost comparisons follow. A typical T8 fluorescent lamp consumes 32-watts. The new basic 4-foot LED retrofit lamp model should consume about 28-watts (20×1.4) based on the published data from Cree Lighting. A 28-watt LED lamp running 12 hours per day at 10 cents per kilowatt-hour uses a total energy cost per year of $12.26 per LED lamp. The total BTU used by the 28-watt LED lamp in one year equates to 122.6 kW or 418,437 BTUs. By comparison, the T8 fluorescent lamp also running 12 hours per day at 10 cents per kilowatt-hour uses a total energy cost per year of $14.02 per T8 fluorescent lamp. The total BTU used by the 32-watt T8 fluorescent lamp in one year equates to 140.16 kW or 478,506 BTUs. Therefore, by using the tubular 4-foot retrofit LED lamp instead of the T8 fluorescent lamp, an end user can see a possible additional savings of $1.76 per year with a difference of 60,069 BTUs saved per retrofit LED lamp used instead of a 32-watt T8 fluorescent lamp.
It becomes evident that the best cost savings with the best overall energy savings option is to use the new tubular LED retrofit lamp powered by direct line voltage AC with the ballast removed or bypassed in existing fluorescent fixtures. The design of the new tubular LED retrofit lamps offers the flexibility for an end user to use it with or without the ballast. As the cost for new high-brightness white LEDs continues to drop, the LED retrofit lamp option running off direct line voltage alternating current will become an even better option for overall cost savings, energy efficiency, and environmental friendliness.
With the addition of power control devices like timers, sensors, and switches being used with the basic LED retrofit lamps of the present invention, additional energy and cost savings can be gained. The use of power control devices is a more intelligent and efficient way to save money on energy bills without sacrificing lighting levels, safety, and lamp life.
According to LaMar Lighting Company located in Farmingdale, N.Y., the average stairwell is occupied less than 5% per 24-hour day or only 1.2 hours a day. During the time of non-occupancy, the LED retrofit lamps with power control devices provide the best energy savings by reducing the power to LED arrays. Other areas of intermittent or limited use including hallways, restrooms, cafeterias, conference rooms and some offices, etc. can also contribute to additional energy savings when using the basic LED replacement lamps with power controlling devices.
The present continuation-in-part application will be set forth in detail in relation to previously mentioned FIGS. 87-97 immediately after the following relevant material from the ancestor patents and applications.
With the present energy crisis, it becomes evident that the need for more energy efficient lamps of all configurations needs to be developed and implemented as soon as possible for energy conservation.
The most effective of all trends in energy-efficient lighting is not a product at all, but complex systems that blend the best of new lighting technologies with intelligent design strategies and ties them both to building automation schemes.
One of these systems, known as “Daylight Harvesting,” employs light level sensors or photosensors to detect available daylight, and then to adjust the output of electric lights to compensate for light coming into an architectural space from the outside.
Daylight harvesting is beneficial from two standpoints: sunlight is good for people, and electricity is expensive, both financially and environmentally. Yet most lighting systems in schools, offices, and retail spaces operate at full output during all hours of operation regardless of how much sunlight is available. The amount of natural light available to any given building differs by geography and the building's design, but on average, the sunlight available to interiors through windows and skylights can provide sufficient light for most educational and business activities.
The financial costs of not turning off or dimming electric lights include unnecessarily high electric bills for lighting and for the air conditioning required to remove heat created by lights. But the total costs go far beyond economics to include eyestrain, because of excessive brightness and even a lessening of emotional and intellectual well-being. Combining good building design with automation to create the process know as daylight harvesting is the preferable way to deal with these problems because, as any facilities manager will say, counting on occupants to manually turn off or dim lights is highly unreliable.
Daylight harvesting in commercial buildings is experiencing renewed interest in the United States, particularly in light of the environmental consequences of power generation, the desire for sustainable design, and current strains on the nation's power grid. The United States Department of Energy estimates that US commercial businesses use one-quarter of their total energy consumption for lighting. Daylight harvesting and its associated systems, therefore, offer the opportunity to reduce energy consumption and costs.
Commercial buildings in the United States house more than 64 billion square feet of lit floor space. Most of these buildings are lit by fluorescent lighting systems. Estimates show between 30% and 50% of the spaces in these buildings has access to daylight either through windows or skylights. The installation of technologies designed to take advantage of available daylight would be an appropriate energy-saving strategy that could potentially turn off millions of light fixtures for some portion of each day.
A building's windows and skylights, or “fenestration,” affect both the daylight available and the energy requirements of a building's heating, cooling, and lighting systems. The definition of fenestration as defined by the Merriam Webster's Collegiate Dictionary 12th edition is the arrangement, proportioning, and design of windows and doors in a building or room. The best way to capitalize on available daylight is to use integrated lighting controls that allow customized light levels and time of day control in use with proper fenestration to reduce energy use and lower power demand.
Daylight harvesting is a system, and all the elements of that system must be considered. Whether dealing with an existing building or a new design, the system begins with fenestration. Next, light compensation must be achieved with gradations of illumination, produced either through switching, or through dimming or brightening to maintain balanced light levels that illuminate without generating unwanted glare.
Lighting controls that respond to daylight distribution via windows, their orientation, location and glazing materials, will complement the abundant natural light available and greatly reduce lighting costs. Efficient lighting systems will also reduce wasted heat, decreasing the cooling load of the entire HVAC system and reducing overall electric usage.
Automatic controls can include the following:                Centralized, web-based control to provide intuitive control that integrates with building automation systems including HVAC and security.        Time of Day control to turn off certain lights according to a schedule.        Timers that automatically switch off lights after a predetermined period.        Occupancy sensors that detect your presence and provide light or turn it off when you leave a room.        Light level photosensors that detect available daylight and modulate output of light accordingly.        
Many current energy codes now require lights to be automatically turned off at the end of the day. Time of Day control provides the capability to schedule lighting based on the day of week and time of day in increments as small as one minute. This type of control ensures that lights are on or off in designated areas at user-specified times.
Another form of scheduling is based on an astronomical clock, which can control outdoor lighting using true on dawn and dusk settings. For example, lights can be turned on thirty minutes before dusk or turned off fifteen minutes after dawn. A building's longitude and latitude settings are used by the lighting control system to calculate dawn and dusk. Typically, an astronomical clock eliminates the need to use outdoor light level sensors.
Maximum energy savings up to 75% can be achieved through control and sensing means where the lighting system is controlled by both daylighting and occupancy sensors. A typical daylight harvesting system using the LED retrofit lamp of the present invention includes at least one light level photosensor paired with dimming controls, and dimming the lights proportionally to the amount of daylight entering the work space. The use of a light level sensor or photosensor will sense the amount of daylight available in a room and adjust the LED retrofit lamp output accordingly. Power control of the LED retrofit lamp can come from at least one occupancy sensor by itself or from at least one photosensor by itself. The use of at least one occupancy sensor in solo or with at least one light level photosensor in an LED retrofit lamp of the present invention will provide for maximum energy savings and conservation.
Many private, public, commercial and office buildings including transportation vehicles like trains and buses use fluorescent lamps installed in lighting fixtures. Fluorescent lamps are presently much more efficient than incandescent lamps in using energy to create light. Rather than applying current to a wire filament to produce light, fluorescent lamps rely upon an electrical arc passing between two electrodes, one located at ends of the lamp. The arc is conducted by mixing vaporized mercury with purified gases, mainly Neon and Krypton or Argon gas inside a tube lined with phosphor. The mercury vapor arc generates ultraviolet energy, which causes the phosphor coating to glow or fluoresce and emit light. Standard electrical lamp sockets are positioned inside the lighting fixtures for securing and powering the fluorescent lamps to provide general lighting.
Unlike incandescent lamps, fluorescent lamps cannot be directly connected to alternating current power lines. Unless the flow of current is somehow stabilized, more and more current will flow through the lamp until it overheats and eventually destroys itself. The length and diameter of an incandescent lamp filament wire limits the amount of electrical current passing through the lamp and therefore regulates its light output. The fluorescent lamp, however using primarily an electrical arc instead of a wire filament, needs an additional device called a ballast to regulate and limit the current to stabilize the fluorescent lamp's light output.
Fluorescent lamps sold in the United States today are available in a wide variety of shapes and sizes. They run from miniature versions rated at 4 watts and 6 inches in length with a diameter of ⅝ inches, up to 215 watts extending eight feet in length with diameters exceeding 2 inches. The voltage required to start the lamp is dependent on the length and diameter of the lamp. Larger lamps require higher voltages. Ballast must be specifically designed to provide the proper starting and operating voltages required by the particular fluorescent lamp.
In all fluorescent lighting systems today, the ballast performs two basic functions. The first is to provide the proper voltage to establish an arc between the two electrodes, and the second is to provide a controlled amount of electrical energy to heat the lamp electrodes. These are to limit the amount of current to the lamp using a controlled voltage that prevents the lamp from destroying itself.
Fluorescent ballasts are available in magnetic, hybrid, and the more popular electronic ballasts. Of the electronic ballasts available, there are rapid start and instant start versions. A hybrid ballast combines both electronic and magnetic components in the same package.
In rapid start ballasts, the ballast applies a low voltage of about four volts across the two pins at either end of the fluorescent lamp. After this voltage is applied for at least one half of a second, an arc is struck across the lamp by the ballast starting voltage. After the lamp is ignited, the arc voltage is reduced to the proper operating voltage so that the current is limited through the fluorescent lamp.
Instant start ballasts on the other hand, provide light within 1/10 of a second after voltage is applied to the fluorescent lamp. Since there is no filament heating voltage used in instant start ballasts, these ballasts require about two watts less per lamp to operate than do rapid start ballasts. The electronic ballast operates the lamp at a frequency of 20,000 Hz or greater, versus the 60 Hz operation of magnetic and hybrid type ballasts. The higher frequency allows users to take advantage of increased fluorescent lamp efficiencies, resulting in smaller, lighter, and quieter ballast designs over the standard electromagnetic ballast.
Existing fluorescent lamps today use small amounts of mercury in their manufacturing process. The United States Environmental Protection Agency's (EPA) Toxicity Characteristic Leaching Procedure (TCLP) is used by the Federal Government and most states to determine whether or not used fluorescent lamps should be characterized as hazardous waste. It is a test developed by the EPA in 1990 to measure hazardous substances that might dissolve into the ecosystem. Some states use additional tests or criteria and a few have legislated or regulated that all fluorescent lamps are hazardous whether or not they pass the various tests. For those states that use TCLP to determine the status of linear fluorescent lamps, the mercury content is the critical factor. In order to minimize variability in the test, the National Electrical Manufacturers Association (NEMA) developed a standard on how to perform TCLP testing on linear fluorescent lamps (NEMA Standards Publication LL1-1997).
The TCLP attempts to simulate the effect of disposal in a conventional landfill under the complex conditions of acid rain. Briefly, TCLP testing of fluorescent lamps consists of the following steps:
1. All lamp parts are crushed or cut into small pieces to ensure all potential hazardous materials will leach out in the test.
2. The lamp parts are put into a container and an acetic acid buffer with a pH of 5 is added. A slightly acidic extraction fluid is used to represent typical landfill extraction conditions.
3. The closed container is tumbled end-over-end for 18 hours at 30 revolutions per minute.
4. The extraction fluid is then filtered and the mercury that is dissolved in the extraction fluid is measured per liter of liquid.
The average test result must be lower than 0.2 milligrams of mercury per liter of extraction fluid for the lamp to be qualified as non-hazardous waste. Items that pass the TCLP described above are TCLP-compliant, are considered non-hazardous by the EPA, and are exempt from the Universal Waste Ruling (UWR). Four-foot long fluorescent lamps with more than 6 milligrams of mercury, for example, fail the TCLP without an additive. The UWR is the part of the EPA's Resource Conservation and Recovery Act (RCRA), which governs the handling of hazardous waste. The UWR was established in May 1995 to simplify procedures for the handling, disposal, and recycling of batteries, pesticides, and thermostats, all considered widespread sources of low-level toxic waste. The purpose was to reduce the cost of complying with the more stringent hazardous waste regulations while maintaining environmental safeguards. Lamps containing mercury and lead were not included in the UWR. Originally, in most states, users disposing more than 350 lamps a month were required to comply with the more stringent government regulations. In Jul. 6, 1999 the EPA added non-TCLP-compliant lamps like those containing lead and mercury to the UWR. This addition went into effect in Jan. 6, 2000. So lamps that pass the TCLP are exempt from the UWR.
Not all states comply with the UWR after Jan. 6, 2000. Individual states have a choice of adopting the UWR for lamps or keeping the original RCRA full hazardous waste regulation. States can elect to impose stricter requirements than the federal government, which is what California has done with its TTLC or Total Threshold Limit Concentration test. In addition to a leaching test, the state of California has a total threshold limit concentration (TTLC) for mercury for hazardous waste qualification. Other states are considering implementing a total mercury threshold as well. California has a more rigorous testing procedure for non-hazardous waste classification. The Total Threshold Limit Concentration (TTLC) also needs to be passed in order for a fluorescent lamp to be classified as non-hazardous waste. The TTLC requires a total mercury concentration of less than 20 weight ppm (parts per million): for example, a F32 T8 lamp with a typical weight of 180 grams must contain less than 3.6 milligrams of mercury. Philips' ALTO lamps were the first fluorescent lamps to pass the Environmental Protection Agency's (EPA) TCLP (Toxic Characteristic Leaching Procedure) test for non-hazardous waste. Philips offers a linear fluorescent lamp range that complies with TTLC and is not hazardous waste in California with other lamp manufacturers following close behind.
Certain fluorescent lamp manufacturers like General Electric (GE) and Osram-Sylvania (OSI) use additives to legally influence the TCLP test. Different additives can be used. GE puts ascorbic acid and a strong reducing agent into the cement used to fix the lamp caps to the fluorescent lamp ends. OSI mixes copper-carbonate to the cement or applies zinc plated iron lamp end caps. The copper, iron, and zinc ions reduce soluble mercury. These additives are found in fluorescent lamps produced in 1999 and 2000. The use of additives reduces the soluble mercury measured by the TCLP test in laboratories and is a legitimate way to produce TCLP compliant fluorescent lamps.
Unfortunately, the additive approach does not reduce or eliminate the amount of hazardous mercury in the environment. More importantly, the additives may not work as effectively in the real world as they do in the laboratory TCLP test. In real world disposal, the lamp end caps are not cut to pass a 0.95 cm sieve, are not tumbled intensively with all other lamp parts for 18 hours, and so forth. Therefore, the additives that become available during the TCLP test to reduce mercury leaching may not or only partly, do their job in real world disposal. As a consequence, lamps that rely on additives pass TCLP, but may still have relatively high amounts of mercury leaching out into the environment.
The TCLP test is a controlled laboratory test meant to represent typical landfill conditions. The EPA developed this test in order to reduce leaching of hazardous materials in the environment. Of course, such a test is a compromise between the practicality of testing a large variety of landfill materials and actual landfill conditions. Not every landfill has a pH of 5 and metal parts are not normally cut into small pieces.
The amount of mercury that leaches out in real life will depend strongly on the type of additive used and the exact disposal conditions. However, the “additive” approach is not a guarantee that only small amounts of mercury will leach into the environment upon disposal.
Several states including New Jersey, Delaware, and Arkansas have addressed the additive issue. They have indicated that if lamps with additives were thrown away as non-hazardous waste and are later found to behave differently in the landfill, then the generators and those who dispose of such lamps could potentially face the possibility of having violated the hazardous waste disposal regulation known as RCRA.
The best fluorescent lamps in production at this time include GE's ECOLUX reduced mercury long-life XL and Philips' ALTO Advantage T8 lamps. They both have a rated lamp life of 24,000 hours, produce 2,950 lumens, and have a Color Rendering Index (CRI) of 85. Rated life for fluorescent lamps is based on a cycle of 3 hours on and 20 minutes off.
Besides the emission of ultra-violet (UV) rays and the described use of mercury in the manufacture of fluorescent lamps, there are other disadvantages to existing conventional fluorescent lamps that include flickering and limited usage in cold weather environments.
In conclusion, a particularly useful approach to a safer environment is to have a new lamp that contains no harmful traces of mercury that can leach out in the environment, no matter what the exact disposal conditions are. No mercury lamps are the best option for the environment and for the end-user that desires non-hazardous lamps. Also, no mercury LED retrofitting lamps will free many users from the regulatory burdens such as required paperwork and record keeping, training, and regulated shipping of otherwise hazardous materials. In addition, numerous industrial and commercial facility managers will no longer be burdened with the costs and hassles of disposing large numbers of spent fluorescent lamps considered as hazardous waste. The need for a safer, energy efficient, reliable, versatile, and less maintenance light source is needed.
Light emitting diode (LED) lamps and organic light emitting diode (OLED) lamps that retrofit fluorescent lighting fixtures using existing ballasts, or other power supplies can help to relieve some of the above power and environmental problems.
An organic light emitting diode or OLED is an electronic device made by placing a series of extremely thin layers of organic film material between two conductors. The conductors can be glass substrate or flexible plastic material. When electrical current is applied, these organic film materials emit bright light. This process is called electro-phosphorescence. Even with the layered configuration, OLEDs are very thin, usually less than 500 nm or 0.5 thousandths of a millimeter. OLED displays offer up to 165 degrees viewing and require only 2-10 volts to operate while OLED panels may also be used as lighting devices. An alternative name for OLED technology is OEL or Organic Electro-Luminescence.
Recent advances made by GE Lighting in the first quarter of 2004 have produced a very bright 24 square inch OLED panel producing well over 1200 lumens of light with an efficacy of 15 lumens per watt and a power consumption of about 80-watts. This latest breakthrough demonstrates that the light quality, output, and efficiency of OLED technology can meet the needs of general illumination on par with todays incandescent and possibly fluorescent lamp technologies. Because OLED panels are thinner, lighter, and flexible by nature, it serves as a possible light source for the present invention.
In the present application, the use of “LED” covers both conventional high-brightness semiconductor light emitting diodes (LEDs) and organic light emitting diodes (OLEDs); semiconductor dies that produce light in response to current, light emitting polymers, electro-luminescent strips (EL), etc. Furthermore, the use of “LED” may refer to a single light-emitting device having multiple semiconductor dies that are individually controlled. It should also be understood that the use of “LED” does not restrict the package type of an LED. The use of “LED” may refer to packaged LEDs, non-packaged LEDs, surface mount LEDs, chip-on-board (COB) LEDs, and LEDs of all other configurations. The use of “LED” also includes LEDs packaged or associated with phosphor, wherein the phosphor may convert radiant energy emitted from the LED to a different wavelength of light. The use of “LED” will also include high-brightness white LEDs as well as high-brightness color LEDs in different packages. An LED array can consist of at least one LED or a plurality of LEDs, and at least one LED array can also consist of a plurality of LED arrays.
These new LED lamps can be used with magnetic, hybrid, and electronic instant and rapid start ballasts, and will plug directly into the present sockets thereby replacing the fluorescent lamps in existing lighting fixtures or with other AC or DC power supplies. The new LED retrofit lamps are adapted to be inserted into the housing of existing fluorescent lighting fixtures acting as a direct replacement light unit for the fluorescent lamps of the original equipment. The major advantage is that the new LED retrofit lamps with integral electronic circuitry are able to replace existing fluorescent lamps without any need to remove the installed ballasts or make modifications to the internal wiring of the already installed fluorescent lighting fixtures. The new LED retrofit lamps include replacing linear cylindrical tube T8 and T12 lamps, U-shape curved lamps, circular T5 lamps, helical CFL compact type fluorescent and PL lamps, and other tubular shaped fluorescent lamps with two or more electrical contacts that mate with existing sockets.
The use of light emitting diodes and organic light emitting diodes as alternate light sources to replace existing lamp designs is a viable option. Light Emitting Diodes (LEDs) are compound semiconductor devices that convert electricity to light when biased in the forward direction. In 1969, General Electric invented the first LED, SSL1 (Solid State Lamp). The SSL1 was a gallium phosphide device that had transistor-like properties i.e. high shock, vibration resistance and long life. Because of its small size, ruggedness, fast switching, low power and compatibility with integrated circuitry, the SSL1 was developed for many indicator-type applications. It was these unique advantages over existing light sources that made the SSL1 find its way into many future applications.
Today advanced high-brightness LEDs and OLEDs are the next generation of lighting technology that is currently being installed in a variety of lighting applications. As a result of breakthroughs in material efficiencies and optoelectronic packaging design, LEDs are no longer used as just indicator lamps. They are now used as a light source for the illumination of monochromatic applications such as traffic signals, vehicle brake lights, and commercial signs.
In addition, white light LED technology will change the lighting industry, as we know it. Even with further improvements in color quality and performance, white light LED technology has the potential to be a dominant force in the general illumination market. LED benefits include: energy efficiency, compact size, low wattage, low heat, long life, extreme robustness and durability, little or no UV emission, no harmful mercury, and full compatibility with the use of integrated circuits.
To reduce electrical cost and to increase reliability, LED lamps have been developed to replace the conventional incandescent lamps typically used in existing general lighting fixtures. LED lamps consume less energy than conventional lamps and give much longer lamp life.
Unfortunately, the prior art LED lamp designs used thus far still do not provide sufficiently bright and uniform illumination for general lighting applications, nor can they be used strictly as direct and simple LED retrofit lamps for existing fluorescent lighting fixtures and ballast configurations.
U.S. Pat. No. D366,506 issued to Lodhie on Jan. 19, 1999, and U.S. Pat. No. D405,201 issued to Lodhie on Feb. 2, 1999, both disclose an ornamental design for a bulb. One has a bayonet base and the other a medium screw base, but neither was designed exclusively for use as a retrofit lamp for a fluorescent lighting fixture using the existing fluorescent sockets and ballast electronics. Power to the circuit boards and light emitting diodes are provided on one end only. Fluorescent ballasts can provide power on at least one end, but normally power to the lamp is supplied into two ends. Likewise, U.S. Pat. No. 5,463,280 issued to Johnson, U.S. Pat. No. 5,655,830 issued to Ruskouski, and U.S. Pat. No. 5,726,535 issued to Yan, all disclose LED Retrofit lamps exclusively for exit signs and the like. But as mentioned before, none of the disclosed retrofit lamps are designed for use as a retrofit lamp for a fluorescent lighting fixture using the existing fluorescent sockets and ballast electronics. Power to the circuit boards and light emitting diodes are provided on one end only while existing fluorescent ballasts can provide power on two ends of a lamp.
U.S. Pat. No. 5,577,832 issued to Lodhie on Nov. 26, 1996, teaches a multilayer LED assembly that is used as a replacement light for equipment used in manufacturing environments. Although the multiple LEDs, which are mounted perpendicular to a base provides better light distribution, this invention was not exclusively designed for use as a retrofit lamp for fluorescent lighting fixtures using the existing fluorescent sockets and ballast electronics. In addition, this invention was designed with a single base for powering and supporting the LED array with a knob coupled to an axle attached to the base on the opposite end. The LED array of the present invention is not supported by the lamp base, but is supported by the tubular housing itself. The present invention provides power on both ends of the retrofit LED lamp serving as a true replacement lamp for existing fluorescent lighting fixtures.
U.S. Pat. No. 5,688,042 issued to Madadi on Nov. 18, 1997, discloses LED lamps for use in lighted sign assemblies. The invention uses three flat elongated circuit boards arranged in a triangular formation with light emitting diodes mounted and facing outward from the center. This configuration has its limitation, because the light output is not evenly distributed away from the center. This LED lamp projects the light of the LEDs in three general zonal directions. Likewise, power to the LEDs is provided on one end only. In addition, the disclosed configuration of the LEDs limits its use in non-linear and curved housings.
U.S. Pat. No. 5,949,347 issued to Wu on Sep. 7, 1999, also discloses a retrofit lamp for illuminated signs. In this example, the LEDs are arranged on a shaped frame, so that they are aimed in a desired direction to provide bright and uniform illumination. But similar to Madadi et al, this invention does not provide for an omni-directional and even distribution of light as will be disclosed by the present invention. Again, power to the LEDs is provided on one end of the lamp only and cannot be used in either non-linear or curved housings.
U.S. Pat. No. 5,575,459 issued to Anderson on Nov. 19, 1996, U.S. Pat. No. 6,471,388 BI issued to Marsh on Oct. 29, 2002, and U.S. Pat. No. 6,520,655 B2 issued to Ohuchi on Feb. 18, 2003 all contain information that relate to replacement LED lamps, but do not disclose the detailed specifics of the original invention.
The following list of U.S. patents and patent publications is made of record and presented for background reference as being related to the present invention disclosure.
Relevant References
1) U.S. Pat. No. 6,739,734 issued to Hulgan on May 25, 2004;
2) U.S. Pat. No. 6,860,628 issued to Robertson et al. on Mar. 1, 2005;
3) U.S. Pat. No. 6,936,968 issued to Cross et al. on Aug. 30, 2005;
4) U.S. Pat. No. 7,049,761 issued to Timmermans et al. on May 23, 2006;
5) U.S. Pat. No. 7,053,557 issued to Cross et al. on May 30, 2006; and
6) U.S. Pat. No. 7,114,830 issued to Robertson et al. on Oct. 3, 2006.
The Timmermans et al. reference is particularly relevant to the present invention for the reason that Timmermans et al. describes a retrofit LED lamp for an existing fluorescent lamp. Timmermans et al., however, does not show, discuss, or suggest any power saving devices associated with the basic retrofit LED lamp as is particularly set forth herein as shown and discussed in FIGS. 87-96 herein, nor does Timmermans et al. utilize voltage suppression devices.
The present invention has been made in order to solve the problems that have arisen in the course of an attempt to develop energy efficient lamps. This invention is designed to replace the existing hazardous fluorescent lamps that contain harmful mercury and emit dangerous ultra-violet rays. They can be used directly in existing fluorescent sockets and lighting fixtures powered directly by line voltage AC where the ballast is removed or bypassed and the tubular LED retrofit lamp of the present invention is connected directly to the line voltage alternating current or direct current voltage.
A primary object of the present invention is to provide a tubular LED retrofit lamp that will bring about better energy conservation and savings.